1. Field of the Invention
The present invention relates to an electroconductive polymer composition, an electroconductive polymer material, an electroconductive substrate, an electrode and a solid electrolytic capacitor.
2. Description of the Related Art
Electroconductive organic materials are utilized as an antistatic material or an electromagnetic shielding material as well as for electrodes of capacitors, electrochemical capacitors or the like, for electrodes of dye-sensitized solar cells, organic thin film solar cells or the like, for electrodes of electroluminescence displays, or the like.
As the electroconductive organic material, electroconductive polymers obtained by polymerizing pyrrole, thiophene, 3,4-ethylenedioxythiophene, aniline or the like are known. These electroconductive polymers are generally provided in a state of a dispersion liquid or a solution in an aqueous solvent, or in a state of a solvent in an organic solvent, and are used as an electroconductive polymer material after the solvent is removed at the time of use.
However, even if the kind of the electroconductive polymer is the same, the property of the electroconductive polymer material obtained is different depending on the production method. Thus, the method for producing an electroconductive polymer composition is variously studied.
JP 2004-59666 A discloses an aqueous dispersion of a composite of a poly(3,4-dialkoxythiophene) with a polyanion. It is disclosed that the aqueous dispersion of the composite is obtained by polymerizing a 3,4-dialkoxythiophene in an aqueous solvent by using a peroxydisulfuric acid as an oxidant in a presence of a polyanion. Also, it is disclosed that it is obtained by adding an acid selected from the group consisting of water-soluble inorganic acids and organic acids to lower the pH of the reaction solution and by polymerizing a 3,4-dialkoxythiophene in an aqueous solvent by using an oxidant in a presence of a polyanion.
WO 2009/131011 A discloses a dispersion of an electroconductive polymer obtained by the electropolymerization of a thiophene derivative in water or an aqueous liquid consisting of a mixed solvent with a water-miscible solvent in a presence of a phenolsulfonic acid novolac resin, a sulfonated polyester or a polystyrene sulfonic acid.
WO 2009/131012 A discloses a dispersion of an electroconductive polymer obtained by oxidation polymerization of a thiophene derivative in water or an aqueous liquid consisting of a mixed solvent with a water-miscible solvent in a presence of polystyrene sulfonic acids and at least one of phenolsulfonic acid novolac resins and sulfonated polyesters.
The methods disclosed in JP 2004-59666 A, WO 2009/131011 A and WO 2009/131012 A are based on the method in which an ammonium persulfate, an iron salt, ethylenedioxythiophene and the like are mixed and reacted in a presence of a polystyrene sulfonic acid aqueous solution to obtain a dispersion of the electroconductive polymer as disclosed in, for example, JP 2636968 B, and the property is improved by changing the production condition. However, the film forming property and the electroconductivity of the electroconductive polymer composition obtained by these methods are not sufficient.
The object of the present invention is to provide an electroconductive polymer composition with a good film forming property and a high electroconductivity. Also, the object is to provide an electroconductive polymer material and an electroconductive substrate with a high electroconductivity and transparency. Further, the object of the present invention is to provide a solid electrolytic capacitor with a high capacity and a low ESR.